Markup Languages have attained wide popularity in recent years. One type of markup language, Extensible Markup Language (XML), is a universal language that provides a way to identify, exchange, and process various kinds of data. For example, XML is used to create documents that can be utilized by a variety of application programs. Elements of an XML file have an associated namespace and schema.
In XML, a namespace is a unique identifier for a collection of names that are used in XML documents as element types and attribute names. The name of a namespace is commonly used to uniquely identify each class of XML document. The unique namespaces differentiate markup elements that come from different sources and happen to have the same name.
XML Schemata provide a way to describe and validate data in an XML environment. A schema states what elements and attributes are used to describe content in an XML document, where each element is allowed, what types of text contents are allowed within it and which elements can appear within which other elements. The use of schemata ensures that the document is structured in a consistent manner. Schemata may be created by a user and generally supported by an associated markup language, such as XML. By using an XML editor, the user can manipulate the XML file and generate XML documents that adhere to the schema the user has created. XML documents may be created to adhere to one or more schemata.
The XML standard is by many considered the ASCII format of the future, due to its expected pervasiveness throughout the hi-tech industry in the coming years. Recently, some word-processors have begun producing documents that are somewhat XML compatible. For example, some documents may be parsed using an application that understands XML.
In XML, it is necessary to maintain a well formed document. Generally, this means that tags within the XML document do not overlap. There are a number of features in word processors, however, that are allowed to span arbitrary ranges. These features include features such as comments, bookmarks, document protection, and the like. What is needed is a way to represent these features in XML.